Refrigerator control device



sept. 16,1941.

v. MocAR-ry REFRIGERATOR CONTROL DEVICE Filed Sept. 12, 1939 5Sheets-Sheet l INVENToR L. V. MCCARTY REFRIGERATOR CONTROL DEVICE sept.16, 1941. .2,256,121

5 Sheets-Sheet 2 Filed Sept. 1 2, 1939 Sept.1 16, 1941. l.. v. MccARTYREFRIGERATOR CONTROL DEVICE Filed Sept. 12, 1939 5 Sheets-Sheet 5 Sept.16, 1941.

L. v. MccARTYl REFRIGERATOR CONTROL DEVICE Filed Sept. l2, 1939 5Sheets-Sheet 4 Sept. 16,1941. L. v. MccARTY REFRIGERATR CONTROL DEVICE 5Sheets-Sheet 5 Filed Sept. `l2, 1959 mmnor Z. MEF.

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VPatented Sept. 16, 1941 l 2,256,121 e REFRIGERATOR CONTROL DEVICELourdes V. McCarty, Milwaukee, Wis., assignor to Edmund E. Allyne,Cleveland, Ohio Application september 12, 1939, serial No. 294,567

7 Claims.

This invention relates to a thermostatic control device forrefrigerators and moreparticularly to a mechanisminfluenced by thetemperatures created in an intermittent absorption type refrigeratingapparatus for turning on and ofi the fuel supply to thegenerator-absorber heating burner.

The present control is responsive to the temperature of the generator atall times; to the temperature of the evaporator during a portion of therefrigerating cycle and to the ambient or room temperature surroundingthe refrigerator during the remainder of the cycle.

The instant mechanism operates by means of thermostatc bulbs to turn onthe flow of gaseous or liquid fuel supplied to the burner under theinfluence of the evaporator temperature and to turn off the flow of fuelunder the iniluence i of the generator temperature with the turn-odbiased by the ambient temperature, e. g., the room temperature.'

Brieiiy stated, the mechanism hereinafter to be described in detailcomprises thermostatic bulbs placed in thel evaporator and adjacent thegenerator for controlling the mechanism ofthe well known intermittentabsorption refrigerating cycle, wherein heat is applied to a generatorby a burner to cause the temperature to rise therein and boil oilaqueous ammonia solution,lwhich is condensed and led to an evaporator.As the temperature of the generator and its associated thermostatic bulbrises, an increase in vapor pressure is created which communicates `withan expanding bellows connected to a mechanism for closing the valvesupplying the fuel to the burner. In the evaporator the liquefiedammonia absorbs heat from the surrounding space and passes into a gaswhich is again absorbed in the generator.

The evaporator bulb communicates with an expansion bellows which isresponsive to ambient temperature and thus when the evaporator reaches atemperature higher than the ambient temperature, the thermostatic bulbis no longer responsive to the evaporator temperature, the bellows thenbeing responsive to the ambient temperature. The evaporatorexpansionb'ellows prevents action by the when the evaporator vortemperature is lower than the ambient temperature. Toward the end of therefrigerating cycle the evaporator temperature rises and when it reaches25 to l5011egrecs'. depending `on position of adjusting knob 81, theevaporator thermostat expands with sufilcient forcel to operate themechanism to turn on the fuel supply for another generating period.

ambient temperature L10/"in pressure in the evaporator thermostatbellows,

' and after a 'predetermined point has been reached 'Ihe arrangementutilizedis such that the senerator turn-of! temperature is dependententirely upon the ambient room temperature. ample, at F. ambienttemperature a generator temperature of approximately 277 F. is requiredto operate to turn off the fuel supply. while at F. ambient temperaturea generator temperature of approximately 366 F. is required. Above 95 F.ambient temperature, the required generator temperature to turn off isapproximately 380 F. 'I'he expansion bellows communieating with both thevgenerator and evaporator thermostats have their respective thrustsopposed to one another so that at any ambient temperature when therequired temperature has been reached in the generator the thrust due tothe generator bellows over-balances the thrust of. the evaporatorbellows causing the fuel valve to close. In this connection when usingliquid fuel the flow of kerosene to the burner is cut-oft but the burneris kept in y'operation for a period of 4 10 to 15 minutes by means ofreservoir supply.

After the flame of the burner dies out, thetemperature oi' the generatorfalls causing a dropping pressure in the refrigerating system, and thusstarts the refrigerating cycle. This decreased temperature likewisecauses a decrease in the vapor pressure in the generator thermostat sothat it is in the position for the next generating cycle.

During the refrigerating cycle the temperature vof the evaporator dropsto a point close to zero degrees Fahrenheit and due to thecharacteristics of the liquid used in the thermostat the temperature ofthe coldest spot in the thermostat determines the vapor pressure on theevaporator bellows. "Ihus the evaporator being colder than the ambientair the evaporator thermostat assumes control and causes a decrease thecontrol mechanism comes into play and againturns on the fuel.y Thisaction is iniluenced by the warming up of the evaporator due todepletion of refrigerant toward the end of the refrigerating cycle.

The objects of. the present control mechanism encompasses the automaticoperation of the deflectors just described and these other objects andadvantages will be apparent from the following detailed description.

In the drawings- F18. device together with 1 is a top plan view of 'afuel control valve actuating Vmechanism shown with the valve open(burner on, generator starting to warm up);

Fig. 6 is a fragmentary elevational view of, the valve actuatingmechanism shown with the valve closed, similar to Fig. 2 (with theburner just turned olf and evaporator cooling off);

Fig. '1 is a fragmentary elevational view of a portion of the actuatingmechanism with the valve on the point of opening;

Fig. 8 is a sectional plan view taken substantially on line 8-8 of Fig.2;

Fig. 9 is a fragmentary elevational 'view of the actuating leversshowing method of adjustment;

Fig. 10 is a diagrammatic view of a refrigerating system using the fuelcontrol device; and

Fig. 11 is a chart of the various time periods and temperaturesinvolved, showing the absorbing and generating periods.

Referring to the diagrammatic representation in Fig. 10 of anintermittent absorption refrigerating system, a generator absorber I isheated 'by means of a fuel burner 2 receiving fuel'from a tank 3. 'I'heflow of fuel to the burner is regulated by the automatic controlmechanism 4 influenced through the medium of thermostatic bulb secured'to the generator absorber and -thermostatic bulb 6 secured to the-evaporator 1.

The automatic fuel control mechanism 4 includes a constant oil levelfeed chamber I6 communicating with fuel supply tankv 3 and has .mountedtherein a vertically movable normally open needle valve II through whichthe fuel passes into the chamber and is discharged therefrom throughopening I2 and thence to the burner 2.

I'he present mechanism is particularly designed to automatically openand close the needle valve and the operating mechanism for accomplishingthis is enclosed within a casing I5 positioned above the lower casingI6. The upstanding partd conduit 23 with the thermostatic bulb 5positioned in the generator-absorber. While any of the well knownthermostatic uids may be used, it is preferable to charge theevappratorbulb with sulphur dioxide, and the generator A.bulb with toluene.

an integral depending portion 3| which extends below the arm 28 and isof slightly reduced width than the upper channel portion of element 26.

Embracing the member 26 and also pivoted to pin 25 is a dependingforwardly extending channel-shaped plate terminating in a pointed end36. tending arm 31 lying parallel to the side of element 21.

Straddling members 26 and 35 is a second depending forwardly extendingchannel-like plate 46 which terminates beyond the end of plate 35.

The forwardly uptumed. end of the plate 46 is split with the mid-portion4| thereof inturned and tapered, while the edge portions 42 areoutturned to form lingers. A snap acting coil spring 43 is positionedbetween'the pointed ends 36 and 4| for a purpose to be hereinafterdescribed.

Lying transversely between the upturned edges of the channel-shapedplate 35 is a pin 45 to which is pivoted a latch or dog 46 whose upperend is adapted to, cooperate under certain conditions with the teeth 36formed on the end of arm 28. A torsion spring 41 encircles the pin 45 tonormally move the latch 46 counterclockwise. The lower inturned bottomportion 48 of the latch abuts a at spring 49 riveted to plate 46.

Also carried on the pin 25 lis a block 56 in which is mounted avertically extending swivel screw 5| which in turn carries a nut 52having rearwardly extending spaced arms 53 engaging pin 54 carried inopposite side bars 55. The side bars 55 are joined by a platform 56 withthe opare journaled in the sides of the'casing and has posite ends ofthe side bars pivoted to pin 51 supported in the sides of verticallyextending channel member 58. This upstanding channel or yoke member isaffixed to transverse pin 66 whose ends a conical depression 6| formedin its lower section for the reception of thrust rod 20 receiving tongue3|, it will be observed that the tongue 3| is being normally urged in aclockwise movement by spring 16 whose opposite endcontacts a button 1|secured to the end of vertically pivoted arm 12. The pivot for this armis mounted in ears 13 formed on transverse plate 14 which extends acrossthe casing. A second and larger spring 15 rests in depression 16 pressedfrom the plate 14 with the opposite end of the spring raising in adepression 11 pressed from the center of dependingl pivoted yoke 86. Theyoke. 86 is vhung on the A horizontal pivot pin 25 is aixed in opposite,

sidewalls "of the upper4 part of .the casing and forms a pivot for'several operating elements which will now be described. As shown in thepivot 25 outside; of the several other pivoted memberspreviouslyfd'escribed and extends downwardly toapproximately the lengthofV tongue 3|. The end of the yok`eg86 is outturned to-form a flange 8|'to cooperate with the lower part of the tongue 3|. Movement of yoke 86is limited by screw 85. A regulating knob 82 carrying a screw 83 is edgeof pivoted plate 12, and it is obvious that the tension of spring 16 maybe varied by'operating the knob to thus retard or advance theturning onpoint 0f the evaporator bellows.

The member 35 also has an upwardly ex.

to snap spring 43 and cause bottom channel mem- 5 ber 40 to raise andpermit the valve stem Il to open in the same manner as that obtained byautomatic engagement of the teeth 30 with the ratchet 46.

The required box temperature is ordinarily l maintained by the automaticbiasing action,`be foredescribed, but manual control for use in coldrooms is obtained by adjustment of the evapora-l tor temperature atwhich the burner is turned on.

Control knob 82 is connected to adjusting screw 15 83, which actsagainst the pivoted adjusting lever 12, which changes the tension ofturn-on spring 10. A clockwise rotation of control knob 82 increases thetension of spring which provides an increased thrust opposed to thethrust A4of the n`2'0 evaporator power element, thus requiring a higherevaporator temperature to affect turn-on. Conversely a counterclockwiserotation of control knob 82 decreases tension of spring 10 whichdecreases the thrust opposed to the evaporator power element permittingturn-on at a lower. evaporator temperature. The4 required turn-ontemperatures are 27 F. for coldest position and 44 to 45 F. for warmestposition.

In operationwhen the evaporator thermostat 30 6 has expanded from theheat it will transmit the power to the bellows I1 and thrust rod i6, seeFigs. 2 and 6. l. In both of these views the needle valve il isillustrated in depressed position to shut off the flow of oil to theburner and the valve is kept against its seat by contacting the upperend of the valve with the bottom of plate 40. In this closed positionthe outwardly ex tending fingers 42 on the plate 40 are in spacedrelation to the upper partof the casing and the snap spring 43 isapplying downward pressure against the point 4I and the latch 46 isresting against the bottom rack tooth 30. This condition was broughtabout by the fluid in the generator thermostat lbeing heated'to such anex- 45 tent that enough thrustwas created in rod 26 to overcome thethrust in rod I6. When this occurs the inward movement of the rod moves.the yoke 58 in a clockwise manner causing pin 54 to move..

horizontally against extending arm 31, which is an integral part ofbottom channel plate 35, and thus carries the outer end 36 thereof in anupwardly direction to cause the snap acting spring 43 to reverse itsposition and force the lower vpivote'd plate 46 downwardly against the55v valve Il to close the same. When the generator thermostat turns offthe supply, as thus described, the parts are in the relation shown linsolid lines in Fig. 6. In closed position during the middle of theabsorbing period the latch 46 is in .engagement with the lowermost racktooth 30 on the arm 28 and remains in this position due to the contactof spring 49 vagainst lower edge 48, as shown in dotted lines in Fig. 6.

After the generator burner has ceased functioning and the generatorpartially cools, refrigeration is resumed and continues^until thesupplyV of refrigerant is exhausted when the evaporator heats up andexpands the fluid in the evaporator thermostat and the thrust rod I6forces the up- 70 per arm 21 of member 26 in a counterclockwisecondition. This moves the latch 46 downwardly and because of itsarcuate, movement permits the end 43 to disengage itself from spring 49and consequently withdraws the latch 46 from en- 7.5

gagement with the teeth 30 and under the influence of coil spring 45pivots the4 latch member against the upward bend in the plate- 35 whichin turn moves the plate 35 downwardly and causes the spring 43 to snapand raise the yplate 40 from engagement with the fuel valve.

As soon as pressure is relieved on the valve it is spring opened.

To recapitulate, when the generator reaches the proper turn-oil heat thegenerator bellows rod presses the upper yoke 58 to force the plate 35and rack assembly, clockwise until the toggle snap spring 43 operatesand moves the plate 40 downwardly to close valve Il. After the fuel isturned off the pawl spring 49 forces the latch I 46 into contact withrack 30. When the generator starts to cool off and the pressure drops,the refrigerating cycle starts and consequently the generatorthermostatic bellows collapse. Thereupon the yoke lever 58 assisted byspring 66 -re` turns to its original position labutting set screw 65Where it remains until the next generating cycle.

The evaporator being cold contracts the fluid in its thermostaticbellows which causes spring- 14 to move lever 26 clockwise until itrests against the casing at the top thereof, as shown in dotted lines inFig. 6. During this movement-l the latch 46 slips past the teeth 30 onarm 28, as shown in Fig. 2. `As the lever 26 starts to move in aclockwise direction the ambient spring 15 abuts its stop screw andceases to be active so that only the turn-on spring 10 is in activ'eposition.

However, when the evaporator heats up, its thermostatic rod begins toforce lever 26 backward in a counterclockwise direction to its originalposition and at a predetermined temperature the lower toothof the rack30 becomes engaged with the pawl 46. Continued movement of lever 26forces plate 35' downwardly to trip the snap spring 43 and thus raiseplate 40 to open the fuel valve I'I.` At this lpoint the pawl 46 becomesdisengaged from the teeth 30 by action of the spring 49.

Referring now to Fig. 11 of the drawings, there is disclosed a chartdesignated as to time and temperature of the several functions andperiods comprising the ref-rigerating cycle, and, as before pointed out,the salient functions of the present method and apparatus are threefold:

, First, the tum-off of the fuel valve at a predetermined generatortemperature.

- Second, the turn-on o f the fuel valve at a pre'- determinedevaporator temperature.

, Third, the automatic biasing or modifying of the fuel valve turn-oil'operations in accordance with the then existing ambient or roomtemperature for the purpose of giving proper box temperature control.

Function i is accomplished by means of the generator thermostaticbellows, while functions Zand 3 are accomplished by the evaporatorther-A mostatic bellows. in further explanation of the' to avoidsubfreezing the food compartment in a 60 F. room, when less`refrigeration is needed, the maximum generator temperature should beabout 275 F. Proper shut-offs at intermediate room temperatures formapproximately a straight line on a graph.

The evaporator temperature characteristics during one complete cycle iscomposed of a gen'- erating (burner on) period and an absorbing (burnerout) period. The evaporator temperature, where the thermostatic bulb ofthe evaporator bellows is located, is alternately below and above roomtemperature, i. e., during the absorbing period the evaporatortemperature goes down tonearly F., and during the generating period theevaporator temperature goes up above room temperature and stays thereuntil after the burner is offalways about 15 F. above room temperatureregardless of what the room temperature is.y To illustrate,'theevaporator temperature when the burner goes out is about 75 F. in a 60F. room, and about 115 F. in a 100 F. room. See chart #2. It isimportant to understand this for it is only because of thischaracteristic that it is possible to combine the two functions (2 and 3above) in one bellows, to be explained forthwith.

The dual functions (2 and 3 above) are performed by the evaporatorbellows, bulb, and connecting capillary tubing which have beenvaporfilled under pressure. Condensing of this vapor takes place at thecoldest spot of the bellowsbulb system, or in other words, the pressureir. the evaporator' bellows is governed by the coldest temperature towhich any part of said system is subjected.

As the control mechanism in which the bellows are mounted, is located atthe front of the refrigerator cabinet near the floor, the evaporatorbellows is always at room temperature for there is practicaly noreflected heat in this position from the burner or other warm unitparts. The connecting capillary tubing, going up the back of the cabinetin the stack, is always above roomA temperature'by reason of reflectedheat from the several warm unit parts. 'Ihe evaporator bulb, however, isalternately above ature, say 90 F., the greater the pressure in theevaporator bellows, so that the lgenerator temperature must go higher inorder for the generator bellows to overcome that .opposing force andshut off the fuel valve. Conversely, if the room is 70 F. at the end ofthe heating period, there is less pressure in the evaporator bellows.Consequently, the generator bellows closes the fuel valve at a lowergenerator -temperature as the opposing force of the evaporator bellowsis not as great as in a 90 F. room.

In this manner, the evaporator bellows performs the dual functions ofopening the fuel valve at a predetermined evaporator temperature andautomatically biasing the closing of the fuel valve according to thethen existing room temperature for the purpose of box-temperaturecontrol.

What I claim is:

l. In a method of control for intermittent absorption refrigerationsystems, the combinasion of temperature influenced means for turning onand turning off the heat supplied to said system together with means tobias the turning off of said heat supply, said means comprising thetemperature influenced turn on means.

2. In an intermittent absorption refrigeration apparatus having agenerator, a heating means therefor, and an evaporator connected inoperative relation, the combination of thermostatically operated meansinuenced by the temperatures of said generator and said evaporator andadapted to turn off and turn on, respecand below room temperature, asexplained above; or in other words, alternately above and below thebellows temperature because the latter is always at room temperature.

During the absorption period, the thermostatic bulb, being nearly 0 F.,governs the pressure in the evaporator bellows and the control -is so.designed that the evaporator bellows will open the fuel valve when theevaporator eventually warms up to the predetermined temperature of 27 F.which at that time is stillthe coldest part of the evaporatorbellows-bulb system. As the generating period progresses, the evaporatorand evaporator bulb warm up to about 15 F. above room temperature andthis differential exists until. after the burner goes out and leaves thebellows, which is at room temperature, the coldest part in thebellowsbulb system.

It is only at theend of the heating period that the function of biasingthe fuellshut-off comes into play, and the control is so designed thatthe pressure in the evaporator bellows `opposes the shut-off action ofthe generator belheating means until the optimum generator temlows.Therefore, the warmer the room tempertively, the said heating means, thesaid turn o of said heating means being retarded by an increase in theambient temperature surrounding said system through the medium of saidevaporator thermostatically operated means.

3. In an intermittent absorption refrigeration apparatus includingagenerator and evaporatorl connected in operative relation, a heatingelement for said generator and thermostatic devices for turning on andturning .off the said heating element, the said thermostatic deviceadapted to turn o said heating element being biased by the ambienttemperature acting on the thermostatic device for turning on saidheating element to advance or retard its operation.

4. An intermittent absorption refrigerating apparatus including agenerator, a heating means therefor and an evaporator, the combi-A natintherewith of a thermostatically operated means associated with saidheating means for turning on and turning off the same and opervated bythe heat of the generator to turn off and by the heat of the evaporatorto turn on,

the thermostatically operated device operated by the said evaporatorbeing rendered operative by an increase in ambient temperature wherebysaid thermostatic device operated by said generator will be preventedfrom turning off said perature is reached for the then existing ambienttemperature. 1

5. In an intermittent absorption refrigerating apparatus, an evaporator,a generator, a

.fuel burner therefor and a fuel supply-valvefor said burner, thecombination therewith, of

a thermostatically operated ymeans for opening and closing saidsupplyvalve, said thermostatic means including an expanding bellowsIinfluenced by the heat of said generator to close said valve and anexpanding bellows influenced by the heat of said evaporator to open saidvalve, the said evaporator bellows adapted to be also influenced by anincrease in ambient temperature to create a bias on said generatorbellows and retard its action in closing said valve.

l.-In an intermittent absorption refrigerating apparatus including anevaporator, a generator, a fuel burner therefor and a fuel supply valvefor said burner, the combination comprising a thermostatic bellows andpush rod operated by the heat of said generator for closing said valveand a thermostatic bellows and push rod normally operated by the heat ofsaid evaporator for opening said valve, a spring biased pivoted leverconnected to said valve and rocked by the thrust action of saidpush-rods to open and close the valve, the said thermostatic bellows andpush rod operated by said evaporator being influenced by ambienttemperature to increase the force on its push rod to retard dtheoperation of the generator bellows push rod. A

'1. In an intermittent absorption refrigerating apparatus including anevaporator, a generator, a fuel burner therefor and a fuel supply valvefor said burner, the combination comprising a thermostatic bellows andpush rod operated by the heat of said generator for closing said valveand a thermostatic bellows and vpush rod normally operated by the heatof said evaporator for opening said valve, a spring biased pivoted leverconnected to said valve and rocked by the thrust action of said pushrods to open and close the valve, the said thermostatic bellows and pushrod operated by said evaporator being influenced by ambient temperatureto increase the force on its push rod to retard the operation of thegenerator bellows push rod at the end of the heating period.v

` LOURDES v. MCCARTY.

